This invention relates to a pneumatic agricultural tire for the drive axle of a tractor or like vehicle.
Farm tires for the drive axle of a tractor have a primary function of providing tremendous pulling traction in soil. To accomplish this task the tread patterns are very open with widely circumferentially spaced elongated traction elements commonly called lugs or bars. Most such tires employ what is called "long bars." These lugs extend from the tread shoulders axially inwardly and some or all of the lugs cross the tread centerline. These lugs or bars commonly have an enlarged lug head at the axially innermost portion of the lug. Such tires are shown in prior art U.S. Pat. Nos. 3,603,370, 4,383,567, and 4,534,392.
The primary limitation of such tires was related to the limited amount of lug edges or surfaces which could be provided for traction. To increase this feature, the named inventor of this patent earlier developed a tire commercially sold as the Goodyear DT710 tire. This tire is described in U.S. Pat. No. 5,046,541. The tire employed four rows of relatively short bars. This increased number of bars provided much more biting edges for traction and as a result has demonstrated significantly superior traction.
Some farmers, however, are reluctant to believe that short bars can be as effective in very wet soils which can tend to pack the tires with mud. Although the DT710 tires perform very well in these conditions, the inventor has attempted to achieve a tractor tire having a combination of long bars and short bars with excellent tractive performance, handling and ride performance and superior tread cleaning properties in sloppy wet soil conditions. To accomplish this result the inventor has designed a unique tractor tread 32 that has a circumferentially continuous row of alternating central lugs 50 which cross at the center of the tread 32.
The tire 20 of the present invention has a very durable design that is believed to be capable of excellent performance in very wet and very dry soil conditions. This multipurpose capability, coupled with the roadworthy handling and ride features, means that a farmer can rely on one set of these tires that will meet the entire range of farming conditions. Currently, farmers must stock a variety of special application tires like rice cane and the like in addition to conventional tires. This inventive tire 20 will make that practice in many cases obsolete and will, therefore, provide a good cost savings for many farmers.